1. Field of the Invention
This invention relates to structure venting, in particular, to a flood vent that opens to permit the flow of water in or out of a structure, such a house or garage, when the water level rises thereby avoiding an excessive pressure differential to develop between the interior and exterior of the structure as well as damage or failure of the structure.
2. Description of the Related Art
To eliminate or at least reduce damage due to flooding, several building code entities as well as the federal government have developed rules and regulations requiring structures with enclosed spaces located below defined flood plain levels to include automatic equalization of interior and exterior hydrostatic pressure caused by floodwaters. The rules and regulations require structures to be designed and built to allow floodwaters to move in and out of a structure freely. The Federal Emergency Management Agency (FEMA) requires compliance with FEMA Technical Bulletin 1-93. Other governmental agencies required compliance with the International Building Code and/or ASME 24-05 and 24-98.
A number of devices have been developed to reduce or eliminate the pressure differential that may develop between the interior and exterior of a structure. In 1935, Hodge developed and was issued in 1938, U.S. Pat. No. 2,105,735 for a device that would relieve pressure that may develop within a closed chamber. The device focused upon the release of gas pressure from within the structure but provided for no means to reduce the pressure differential that could develop when the internal pressure of the closed chamber was less than the surrounding pressure. In 1954, Wolverton filed an application for a double acting relief valve and was issued a U.S. Pat. No. 2,774,116 in 1956. Wolverton's double acting relief valve addressed the shortfall for Hodge's device by double hinging a plate mounted in a structure's door that would activate to equalize the pressure differential, if any, between a storm door and main door. The Wolverton device did not address the issues associated with pressure differentials created by floodwaters, nor did the Wolverton device address ventilation.
In 1993, Wagedes filed an application for an improved louvered basement vent and was issued U.S. Pat. No. 5,293,920 in 1994. Wagedes' improved louvered basement vent included a frame and a screened opening. The louvers could be held open by engaging louver detents against frame tabs. The louvers open automatically to relieve excessive pressure in the structure and would remain open if the louvers engaged the frame tabs. While the Wagedes improved louvered basement vent was screened—where the prior discussed patents were not, it was limited to addressing only one type of pressure differentials—namely over pressurization of the structure. Furthermore, the Wagedes improved louvered basement vent required human intervention to reset the louvers in a closed position if the detents were engaged.
In 1994, Schedegger and others filed a patent application for a plastic foundation vent and were issued U.S. Pat. No. 5,487,701 in 1996. The Schedegger device is similar in construction to the Wagedes device, in that it comprised independent louvers that could be held in an open position as well as a screened opening. Like Wagedes' device, Schedegger's device was limited to addressing only one type of pressure differential and required human intervention to release opened louvers.
In 1999, Montgomery filed a patent application for a device and method for relieving flooding from an enclosed space. He was issued U.S. Pat. No. 5,944,445 in 1999. The Montgomery device includes a swinging door capable of swinging both in and out of the structure to permit tidal water flow in and out of the structure. The swinging door has a spring loaded hinge and is held in a closed position by a catch assembly. The catch assembly includes an adjustable screw, a catch spring, a ball bearing and threaded sleeve. The automatic opening of the device in response to floodwaters pressing against the door is a function of adjusting the catch assembly. Improper adjustment of the catch assembly could range from a premature door opening (by animals) to failure of the door to open. Furthermore the manufacturing and assembly of such a device require skilled labor. In the same year, Montgomery and other filed a patent application for a foundation flood gate with ventilation. U.S. Pat. No. 6,287,050 was issued in 2001 for the device. Like his previous device, the foundation flood gate with ventilation included a swinging door capable of swinging in both directions to allow water to flow in or out of the structure. Automatic activation of the door is performed by a catching assembly. The catching assembly included a float for sensing the level of the water and releasing the door when the level exceeds a preset height. Automatic opening of the door requires an intact and freely movable float within the device. While requiring fewer parts than his previous device, the catching assembly still requires skilled labor to manufacture and assemble. In 2001, Montgomery and others filed a similar application for a foundation flood gate with ventilation but the latch assembly senses fluid force acting upon the door rather than relying upon a float to sense water level. In 2002, the United States Patent and Trademark Office issued U.S. Pat. No. 6,485,231 for the device. The device included a latching assembly which requires skilled labor to manufacture and assemble for proper operation.
Sprengle and other filed an application in 2002 for a flood gate for a door. In 2004, U.S. Pat. No. 6,692,187 was issued for the device. The Sprengle device incorporated both the pressure and float sensing features of Montgomery's devices and further allowed for the gate to be used in an overhead door application without the door automatically swinging open when the overhead door is opened. Like the Montgomery devices, the Sprengle device requires skilled labor to manufacture and assemble for proper operation.
Finally, in 2007 Albanese was issued U.S. Pat. No. 7,270,498 for a flood vent which relies upon a door with floatation slideably mounted to a frame which automatically opens (or closes) based upon the level of the floodwaters. While Albanese reduces the number of moving parts and thereby reduces the need for skilled labor, the device still requires proper manufacturing tolerances and assembly to ensure free sliding movement of the door within its tracks. Furthermore the Albanese device has no means to automatically open in response to force upon the door.
As can be seen above the need for a flood vent that can open automatically, provide ventilation, yet have a minimal number of moving parts is desirable.